Stencil-sheet for autographic apparatus.



UNITED STATES PATENT OFFICE.

KURT WALTER, OF BERLIN, GERMANY.

STENCIL-SHEET FOR AUTOGRAPHIC APPARATUS SPECIFICATION forming part ofLetters Patent No. 660,606, dated October 36, 19 06.

Application filed J nuary 13, 1900; Serial No. L401. (No specimens.)

To all whom it may concern:

Be it known that I, KURT WALTER, a subject of the King of Saxony,residing at Berlin, in the Kingdom of Prussia and German Empire, haveinvented certain new and useful Improvements in Stencil-Sheets forAutographic Apparatus, of which the following is a specification.

The subject of the present invention is an improved stencil-sheet forautographic apparatus -such as the mimeograph, cyclostyle, and thelikewhereby a large number of copies of a document are produced. Withsuch apparatus, as is well known, use is generally made of a sheet ,ofpaper or tissue, which receives a film of suitable material. Theprepared sheet is then laid upon a plate having a surface ruled toresemble the face of a file and written upon with a style, or it may belaid upon a smooth plate and written upon with a style having asmall-toothed wheel as the writing-point,whereby the prepared sheet isperforated, forming a stencil. The sheet is then laid upon the paper onwhich the copy is to appear and ink pressed through the perforations bymeans of a roller or the like.

Hitherto paraffined tissue-paper has principally been used for thestencil-sheet; but this it is found has many disadvantages. Theparaffin, for instance, clogs the finelyruled surface of the plate onwhich the stencil-sheet lies orin similar manner blocks up the teeth ofthe wheel of the style, so that sharp perforations cannot be made.Paraffin-paper, moreover, becomes very easily friable, and in writingrapidly cracks occur, greatly disfiguring the copy. A furtherinconvenience in the case of paraffin-paper is that it cannot besufliciently tightly stretched, whereby in applying the ink the sheetcreases under the roller, so that in some places the writing isduplicated or shifted out of position. All these disadvantages areovercome by means of the improved stencil-sheet forming the subject ofthe present invention. This new sheet is composed of the externalmembrane or coats of the large intestine of cattle, such as is known inpharmacy as emplastrum animale. This membrane, as is well known, isextremely thin, but at the same time remarkably tough and capable ofbeing stretched to a high degree. It can be employed for the purpose inquestion with out any parafiin or other film having to be applied to it.The perforations produced in it when laid on a ruled plate and writtenupon with a style are extremely sharp and uniform, and it is capable ofbeing stretched so exceedingly tight that creasing under theinking-ro'ller is impossible.

In order to adapt the intestinal membrane for use as a stencil-sheet, Iprefer to treat it with water and acid um sulfurosum. For this purposethe membrane is set in a bath, which may advantageously consist of onepart acid um sulfurosum and nine parts Water. Any other acid, however,which is capable of ungreasing such membrane may be employed. Nor do Ilimit myself to the precise proportions of acid and water. After suchtreatment I then stretch the membrane over a rack or the like until itbecomes exceedingly thin, presenting an absolutely-smooth surfaceresembling a very thin tightly-stretched drumhead. I leave the membranein this stretched condition for some time and dry it, when it isadmirably suited for the purpose in view.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is

1. A stencil-sheet for autogra'phic appara tus, composed of externalcoats of the large intestine of cattle, as described.

2. A stencil-sheet for autographic apparatus, composed of intestinalmembrane treated by being stretched in wet condition over a rack anddried, substantially as described.

3. A stencil-sheet for autographic apparatus, composed of external coatsof the large intestine of cattle, prepared by being treated with waterand acid, stretched in wet condition over a rack and dried,substantially as described.

In witness whereof I have hereunto signed my name, this 23d day ofDecember, 1899, in

Witnesses WOLDEMAR HAUPT, HENRY HAsPER.

